A Double pipe heat exchanger whose inner pipe is expected to be made of copper and the outer Jacket is to be made of schedule $40$steel$.$ Two fluids A and B flow though the pipes and are involved in heat transfer. The inlet and outlet temperatures of the hot fluid is C and D and that of the cold fluid is E and F respectively.

i$)$Design a suitable double pipe heat exchanger

A $=$Methylene glycol

B $=$Isobutane

C $=99$c

D $=79\mathrm{.}5$c

E $=15\mathrm{.}3$c

F $=27$c